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(No Model.)

W. SCHMIDT.V

EEED WATER. HEATER. No. 572,573. Patented Dec. 8, 1896.

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WILHELM SCHMIDT, or BALLENSTDT, GERMANY;

FEED-WATER HEATER.,

' srncIFIcA'rroN forming pere ef Letters reten No. 572,573, aerea December 8,1896.

' Applicationliled February 3l 1896. Serial Nm 577,961. (No model.) I

To all whom, it may concern:

Be it known that I, WILHELM SCHMIDT, a subject of the King of Prussia, German Emperor, and a resident of Ballenstadt-on-the- Harz, in the Duchy o f Anhalt, in the German Empire, have invented certain new and useful Improvements in Feed-Water Heaters, of which the following is an exact specification.

It is known that to exhaust the waste gases of a steam-boiler furnace by let-ting them heat the feed-water large surfaces are requisite if that exhaust -is to bea somewhat considerable Said large surfaces necessitate generally a great space, which is tolerably reduced only if the feed-water heater is Aformed by coiled pipes. Thereis, however, then created another drawback that consists in the clogging of said pipes by incrustated sediments. These latter, before causing the iinal clogging of the pipes, hinder them from properly transmitting the heat of the waste gases upon the feed-water, and the-exhaust of said gases is thereforel an unsatisfactory one.

The object of my invention is to overcome all the said drawbacks, and I attain that object in general by inclosing a certain quantity of pure water within a coil one part of which is acted on by the waste gases of a boiler-furnace, whereas the other part acts in its turn upon the feed-water. The end of said coil is connected with the commencement of the same, or vice versa, and the pure water that circulates quickly or is artificially caused quickly to circulate through and within the coil receives the heat of the waste gases and transmits it to the feed-water. The heat of the waste gases is thus taken up by a coil or coils; but there is no possibility of the latter getting clogged, as the water circulating Within the coils has originally been introduced in a pure state and remains so.

In order to make my invention more clear, I refer to the accompanying drawings, in which similar letters denote similar parts throughout the dierent views, and in which- Figure l is a vertical longitudinal section through the rear portion of a Cornwall boiler that is furnished with my novel arrangement. Fig. 2 shows said arrangement combined with an upright boiler of a particular construction, and Fig. 3 is a horizontal section taken on line 4 5 of Fig. l.

Thetransmission of the heat upon the feed water takes place within the feed-water heater a, Figs. l and 2, that contains the cylindrical coil b. The latter is illed with pure water, which flows, as a matter of course, in a downward direction, whereas the feed-water enters the vessel or at the bottom thereof and leaves it in a heated state at the top. It is obvious that by this. means the feed-water is highly heated, whereas the pure water isvcorrespondingly cooled. The latter, when leaving the coil b, passes into the coils b', Figs; l and 2, that are arranged in the way of the nre-gases streaming forth from the furnace of the respective boiler. Said coils b' offer the last surfaces that can usefully consume the heat of the escaping fire-gases, and said heat is transmitted to the pure water that comes down from the cylindrical coil b, passes through the coils b', and iiows again'up to said cylindrical coil b. The coils ZJ b form a continuous way and may practically be regarded as one serpent consisting of two parts. In either of said parts the direction of motion of the respective two media is one opposite to the other.

In the form of construction represented in Figs. l and 3 I have shown my novel arrangement combined with a flametube boiler that is furnished with a throttle-valve R, or other equivalent device, for regulating the temperature as well as quantity of the fire-gases flowing from the {lame-tubeinto the vaulted chamber K. The latter forms a part of the conduit that leads the waste gases to the chimney. The heat of said gases is taken up in two stages, in that the said gases are first caused to wash a superheater S, that, consists of coiled pipes and is arranged above the coils b aforementioned. The size of said superheater is, as a matter of course, chosen so as to superheat the steam of the boiler up to the degree desired. y

The coils b', that contain the pure water for transmitting the remainder of the heat of the waste gases upon the feed-water within the vessel @are thus washed by the waste gases only after these latter have acted upon the superheater S. Owing to the greatly-reduced temperature of said gases when arriving at the coils b the water within the latter can never get exposed to a stronger pressure than ICO the boiler-Water proper, and I am thus enabled to connect the coils b b with the steamspace of the boiler by means of a pipe g. The purpose of this connection is to allow of the steam replacing that part of the pure water contained within said coils b b/ that has got lost by leakage and the like. Other devices for filling, in such a case, the coils b b may thus entirely be dispensed with.

Instead of letting the pure waterwhen passing through the coils b run fully in a direction opposite to that of the waste gases I may in some cases lead it partly in said latter direction and partly in a direction opposite to the former, or equal to that of the waste gases, respectively. Such a modification of the method is necessary in all boilers in which the waste gases flow in an upward direction, as is especially the case with upright boilers'.

In the correspondingly-modied arrangement shown in F ig. 2 the pure water coming from the feed-water heater a passes through the coils b in a downward direction, i. e., opposite to the direction of the furnace-gases. The number and length of said coils is so chosen that the water cannot be turned into steam. The water is then led by the mediation of a pipe b2 into the lowermost of a number ofv coils 3, arranged below the coils Said coils b3 are exposed to far hotter gases than the coils b', and a part of the hot water flowing through the coils b3 is therefore turned into steam. The mixture of hot water and steam iiows finally upward through the pipe f. By these means I not only gain the difference in weight between the hot water and the cooled water as' a mot-ive power for causing the water to circulate through the coils, as in Figs. l and 3, but moreover I increase that effect by letting a part of the water be turned into steam, so as to obtain a still greater difference in weight, as in- Fig. 2. The fast circulation of the water is very advantageous if the temperature of the waste gases is a somewhat high one.

The water and steam separate when escaping from the upper end of the pipe f. rlhe water is collected byavessel e and led off by a pipe d to the connecting-pipe b2 aforementioned. The steam enters thc cylindrical coil b within the feed-water heater CL and condenses again to pure water while giving its heat off to the feed-water. Said water then passes into the coils b/ and the circuit aforedescribed commences anew. The fact that the speed of the water when flowing through the coils b' is considerably lower than when flowing through the coils b3 affords twoimportant advantages: first, by the slow speed of the water within the coils ZJ the heat of the waste gases is very thoroughly consumed; second, by the fast speed ol' the water within the coils b3 the latter are very effectively prevented from being burned.

Thewater collected within the vessel c need not all be led off into the pipe b2 or the coils b3, respectively, but the quantity of the water .a superheater.

led over into said parts b2 or b3 may be regulated according to the temperature of the iiregases, preferably by a cock H or other equivalent means. Owing to the insertion of theV vessel e between the coils 'b3 and b the passage of the steam from the pipe f to the coil b occurs free of shocks. Said vessel may, if desired, be furnished with a gage-cock or gage-glass, as well as with a funnel or other device for filling fresh pure water into the ap paratus if a part of the previous Water has got lost by leakage or the like. Said cock and funnel or equivalent parts may, as a matter of course', be arranged also at other suitable parts of the apparatus.

Also in the modified construction shown in Fig. 2 the coilsv b b3 may be combined with The latter may be arranged either below said coils (or, in other words, in front of the same with regard to the direction of the lire-gases, as in Fig. l) or between the set of coils b and the set of coils b3, but other arrangements may as well be chosen.

Having thus full-y described the nature of my invention, what I desire tosecure by Letters Patent of the United States isl. As a means for exhausting the waste gases of a boiler-furnace, the combination with a steam-boiler and furnace, of a hollow heating-body arranged within the way of the waste gases of said furnace, and of another hollow heating-body connected at both ends with said former body, arranged within a feedwater heater, and communicating with the steam-space of said boiler, said hollow heating-bodies containing pure water, for the pur pose asdescribed.

2. As a means for exhausting the waste gases of a boiler-furnace, the combination with a steam-boiler and furnace, of a set of coils arranged within the way of the waste gases of said furnace, and of another set of coils connected at its lower end with the lower end of said former set, and at its upper end with the upper end of the said former set as well as with the steam-space of said boiler; said sets of coils containing pure water, for the purn pose as described.

3. As a means for exhausting the waste gases of a boiler-furnace, the combination with an upright steam-boiler and furnace, of a set of coils arranged above said boilerwithin the way of the waste gases of said furnace; another set of coils arranged above said former set, and connected at its lower end with the lower end of the said former set; a third set of coils arranged within a feed-water heater, and connected at its lower end with the upper end of said second s et, and communicating at its upper end with the upper end of the first set by the mediation of a water-trap, said sets of coils containing pure water, for the purpose as described.

4l. As a means for exhausting they waste gases of aboiler-furnace, the combination with an upright steam-boiler and furnace, of a set of coils arranged above said boilerwithin the way IOO IIO

of the waste gases of said furnace; another set of coils arranged above said former set,

and connected at its lower end with the lower end of the said former set; a third set of coils' arranged within a feed-water heater, and connected at its lower end with the upper end of said second set, and communicating at its upper end with the upper end of the first set by the mediation of a water-trap; said sets of coils containing pure water; the Water-space of said trap being connected by a pipe with the rst set of coils; a cook or Valve inserted into said pipe, for the purpose as described.

5. As ameans for exhausting the waste gases of a boiler-furnace, the combination with a steam-boiler and furnace, and with an enlarged conduit communicating at its upper with said chimney, of a set of coils arranged Within said enlarged conduit; another set of coils arranged within a feed-water heater, and connected at both ends with said former set; said two sets of coils containing pure water; a steam-superheating set of coils arranged above said first set, and connected at one end with the steam-space of the said boiler; a regulating-valve arranged between the said 4enlarged conduit and the said furnace, for

the purpose as described.

In testimony whereof I have signed this specification in the presence of two subscrib- 

